Extended Data Fig. 3: Results of the Bayesian retrieval for the interior structure of HD 149026b.

Mass is in Jupiter masses and age is in gigayears. Z_p and ε are unitless and refer to the bulk metallicity of the planet and the log₁₀ of the hot Jupiter heating relative to the incident flux, respectively. The retrieval shows that the planet is very metal rich irrespective of the exact age or heating rate. The structure models are from ref. ¹¹ and the statistical model is from ref. ¹² Note that the planet radius (accounting for uncertainty) was a vital observation which the model seeks to explain, but it is not a model parameter and so is not shown in the posterior.